0:12Skip to 0 minutes and 12 secondsHELEN TRUBY: An adult's energy balance works by simply, the arithmetic between energy in and energy out. So energy that we have from our food and our drink is obviously energy in. That needs to balance the amount of energy we're actually expending in activity. So our bodies also use a basic amount of energy every day. There are numerous studies around that have tested various different diets, and the answer is they all perform reasonably well. The challenging aspect is ensuring that you can maintain that dietary pattern over a period of time, so you can keep that lost weight off. Recent popularity in terms of diets has been modified fasting.

0:53Skip to 0 minutes and 53 secondsSo in other words, not eating on certain times of the day, or whatever. And again, if that's a mechanism whereby people find that they can manage their weight, then well and good. The only issue is around diet quality-- in other words, nutrient density. So if you're going to skip a couple of meals twice a week or three times a week, you need to make sure that you're going to get your micronutrients that you need that you're going to miss out on, simply by not eating later on in your diet-- particularly important for women, in our iron requirements. Particularly important for women of childbearing age as well, if you're planning a pregnancy.

1:31Skip to 1 minute and 31 secondsSo there are elements of lifestyle as well that's important. And picking something that you're going to be able to stick to. But in all honesty, most of them will work for you as long as you reduce your overall energy intake. You will lose weight. That's physiologically the way it sits. So activity, whether it comes in the form of walking, standing, running, anything like that, it's going to burn energy. So that adds to our energy out equation. And one of the issues that we have largely in our society now is that people are very sedentary. So we don't do a lot of physical activity everyday. And the more sedentary we are, really the less energy we actually need to have.